Such a dispensing assembly is particularly advantageous for ophthalmological treatments. This is because 5 to 10 microliters (.mu.l or mm.sup.3) suffice for washing the surface of the eye. Even the finest of normal droppers deliver drops whose volume is too great. As a result, excess liquid deposited on the cornea runs into cavities and over nasal mucus membranes. This constitutes a loss of active substance, and may even be counter-indicated. The present invention therefore seeks to provide a device capable of generating and delivering a drop of very small volume, about 10 mm.sup.3 or less.
Another aim of the invention is to provide a device that guarantees delivering only one drop at a time. The finest of presently-available droppers often suffer from the following drawback: they are difficult to operate, and if the user maintains pressure a little too long on a rubber bulb, for example, then a large number of drops are delivered almost simultaneously. This risk is increased when the user is in an uncomfortable position while operating the dropper, as is the case for eye treatments.
Finally, the present invention seeks to provide a dispensing assembly which includes not only a dispenser device having the above-mentioned qualities, but also a supply of substance commensurate with the operation of the device. Given the very small volume of the drops dispensed, the supply must also be small in size. This gives rise to a problem in the ease with which the dispensing assembly can be handled.